Ask New Yorkers to name their favorite public spaces, and chances are you’ll end up with a list that includes Central Park, Grand Central Terminal, maybe Rockefeller Center, and the main reading room at the New York Public Library. Depending on geography, you might hear some outer-borough suggestions, but without a doubt the list would be a mix of public and private initiatives, which is telling about the nature of New York.

Because they have been adopted so thoroughly into the fabric and affections of the city, it is easy to forget that spaces like Grand Central were built by a private entity—and in this case, a fairly ruthless one: the Vanderbilts’ New York Central Railroad. You might recall that the company’s main rival, the Pennsylvania Railroad, scored a victory in opening Pennsylvania Station, which broke the New York Central’s monopoly on bringing riders and goods directly into Manhattan. And Penn Station’s loss reverberates to this day in the decade-long struggle to replace it by turning the Farley Post Office into Moynihan Station. One of the revealing things about that tale is the changing ratio of public to private: After many years of looking at the conversion as a primarily transit-based and publicly-funded initiative, there was very little progress; the breakthrough came when the scope of the proposal expanded dramatically to include many more uses and buildings. There is a certain symmetry in the fact that Penn Station was built by one titan, and may well be rebuilt by two others.

As this story shows, few issues in New York City are ever clean-cut and straightforward, and responsibility for the public realm can be messy. As public funding for things like schools and parks gets harder to come by, and developers are willing to include public programming in order to build higher, the mix has gotten more and more common (see Matt Chaban’s “You Get What You Pay For” in this issue). Some argue that the public is always on the losing end of the deal, and that the practice is poor policy. There are dozens upon dozens of examples where New Yorkers have been sold out for a pallid and useless “amenity,” but it is also a problem to conflate public funding with public life. City streets and spaces and rooms become important parts of the public realm when people want to use them, and there are a thousand reasons—the distance is shorter, there are more shade trees, the people are more fun to watch—why we choose one place over another. Just because we declare something to be civic-minded or off base doesn’t mean people will see it that way—just look at the city’s unofficial network of public bathrooms, a.k.a. Starbucks.

One of the more successful examples of a blend between public and private is the renovation of the High Line. From the homegrown crusade of two neighbors to a centerpiece of the city’s agenda for public space and an extraordinary incentive for private development, the project has shown that in some cases, blurry lines may be in the city’s best interest.